Design and Simulation of MEMS based Varactor with High Tunability for Digital Communication Systems

This paper presents a novel design and simulation of 3-bit RF MEMS tunable capacitor for digital communication systems. Proposed varactor design consists of three parallel plate capacitors connected with truss beam. There are slices in parallel plates to increase the area tuning capability of varactors. A new beam design is proposed to reduce the stiffness of the beam which results in reduction of pull in voltage to 4.5 V. The length and width of beam is 718 11m and 80 11m. A standardized process is used for fabrication process. There are nine states of capacitance and at pull in voltage of 4.5 V maximum tunability is achieved that is 168%. Total varactor design dimensions are 900 11m x 750 11m. The beam has 2 11m thickness and low losses CPW made up of gold material. Mechanical simulation is done on INTELISUIT Software while electrical analysis done on CST microwave studio.